Hello, I am using monad-coroutine <https://hackage.haskell.org/package/monad-coroutine> package and have something like Coroutine (Await Int) (State MyState) Int (simplified version, for example purpose). MyState is deeply nested and I do a lot of modifications in it. Previously (with different data types) I was able to use zoom from lens <https://hackage.haskell.org/package/lens>in order to simplify the typing/view of code which operates on some subtree of the state, e.g.: zoom (company.assets) $ do something.a = someComputation anotherthing.b = False this.that = "someString" The problem I am having is that I cannot come up with instance Zoom for the Coroutine and was wondering if anyone is able to help me with that? Best regards, Konstantin